Stabilized pesticidal wettable powder formulations

ABSTRACT

The invention provides stabilized pesticidal formulations containing at least one 4,6-dinitro-2-sec.butylphenyl ester as active ingredient and as a stabilizing agent a sodium dinaphthylmethane disulfonate having unsatified free sulfonic acid groups.

United States Patent 1 Albrecht Feb. 27 1973 STABILIZED PESTICIDAL WETTABLE POWDER FORMULATIONS [75] Inventor: Konrad Albrecht, Frankfurt am Main, Germany [73] Assignee: Farbwerke Hoechst Aktiengesellschait vormals Meister Lucius & Bruning, Frankfurt am Main, Germany 221 Filed: Dec. 2, 1969 21 Appl. No.: 881,587

[30] Foreign Application Priority Data Dec. 5, 1968 Germany ..P 18 12 947.0

521 U;s.c1....-.' 71/106, 71/120, 71/1310. 1, 424/311, 424/337 51 1111.01. ..A0lu 9/24 [58] Field of Search....71/l06, DIG. l, 120; 424/311,

Primary Examiner-James 0. Thomas, Jr. Attorney-Curtis, Morris & Safford [5 7] ABSTRACT The invention provides stabilized pesticidal formulations containing at least one 4,6-dinitro-2-sec.butylphenyl ester as active ingredient and as a stabilizing agent a sodium dinaphthylmethane disulfonate having unsatified free sulfonic acid groups.

8 Claims, No Drawings STABILIZED PESTICIDAL WET-TABLE POWDER FORMULATIONS The present invention relates to stabilized pesticidal Wettable powder formulations.

Esters of 4,6-dinitro-2-sec.butylphenol (DNBP), for example binapacryl [3-methylcrotonic acid 2-secbutyl-4,6-dinitrophenyl ester] and dinoseb acetate [acetic acid 2-sec-butyl-4,6-dinitrophenyl ester], are used, depending on the type of acid used for esterification, as acaricides, fungicides or herbicides. The speed of hydrolysis into the free DNBP is influenced by the constitution of the acid, this having undesired consequences in formulations of the said esters as Wettable powders. The formation of free DNBP limits the selectivity of herbicidal compositions. Also, free DNBP is toxic and with acaricidal preparations it causes phytotoxic damage. Moreover, the formation of DNBP in higher concentrations involves a break-down of the physical properties of the respective formulations. The suspendability rapidly diminishes in storage and no longer meets international requirements.

As dispersing agents for the Wettable powder formulations there are generally used the sodium salts of alkyl-naphthalene-sulfonic acids, dinaphthylmethanesulfonic acids, alkyl-benzene-sulfonic acids, as well as oleyl methyl tauride, sodium lignin sulfonates or partially saponified polyvinyl acetates.

Owing to its good dispersing properties'and minor foam formation the sodium salt of dinaphthylmethanedisulfonic acid, which ensures the required suspension properties, has preferably been used for highly concentrated wettable powders of DNBP esters and the combinations thereof with urea herbicides. A 10 percent solution of the said sodium salt in distilled water has a pH value of 7 to 8. It is evident from the following ex amples that products containing this dispersing agent are stable in storage to a limited extent only. DNBP is formed and causes the aforesaid damages.

Additions of polypropylene glycol exhibit a stabilizing effect only in the case of binapacryl. But non ionic components of this type have the drawback that in most cases the Wettable powders formulated therewith cannot be mixed with other Wettable powders as the latter flocculate in the spray liquor. Additions of 2 to percent of acid components, such as sodium bisulfate, alkylphosphoric acids, alkylsulfonic acids or tolylbenzene-sulfonic acids, do not improve the storability and stability of the active ingredients.

It has now been found that a not completely neutralized sodiumdinaphthylmethane-disulfonate still carrying free sulfonic acid groups, which, if measured in a 10 percent aqueous solution has a pH of 5 to 6.8, preferably 6.4 to 6.8, is suitable in an amount of from 4 to percent by weight, preferably 6 to 10 percent by weight, calculated on the total mixture, can be'used as a stabilizing dispersing agent for wettable powders of DNBP esters such as binapacryl and its acaricidal combinations with tetradifon [4-chlorophenyl-2,4,5- trichlorophenyl sulfone] or tetrasul [2,4,4',5- tetrachlorodiphenyl sulfide]. The stabilizer can also be used with agents such as dinoseb acetate and its combinations with urea herbicides, preferably monolinuron [3-(4 l -methoxy-l-methylurea]; linuron [3 3 ,4-dichlorophenyl l -methoxyl -methylurea] neburon [l-butyl-3-(3,4-dichlorophenyl)-l-methylureal; diuron [3-(3,4-dichlorophenyl)-l,l-dimethylurea]; [3-(4-chlorophenyl)-l,l-dimethylurea]. In the finely ground Wettable powders the stabilizing dispersing agent confers upon the active ingredients the necessary stability so that acaridical formulations thereof do not cause phytotoxic damage and in wettable herbicidal powders the selective range of efficacy and the suspension properties are maintained for a storage time of 2 to 3 years (according to general experience a stability in storage of 1 month at 50 C corresponds to a stability in storage for 1 year at normal temperature). Thus combination formulations of DNBP esters with urea herbicides could be prepared for the first time.

The dispersing agent having the stabilizing effect can be obtained, for example, by neutralizing an aqueous solution of free dinaphthylmethane-disulfonic acid with sodium hydroxide solution, sodium carbonate or sodiurn hydrocarbonate until a sample of a 10 percent aqueous solution thereof has the specified pH value and then evaporating the solution to dryness.

In the following examples there are compared the properties of an unstable" formulation containing sodium dinaphthyl-methane disulfonate having the conventional neutral pH of 7 to 8 with a formulation containing sodium dinaphthylmethane disulfonate having the stabilizing pH of 6.4 to 6.8 as regards the formation of free DNBP and the suspension property of the respective formulations after prolonged storage.

Example 1 Wettable powder with 40 percent of dinoseb acetate Wettable powder with 37.5 percent of dinoseb acetate and 12.5 percent of monolinuron a) unstable composition b) stabilized 37.5 k of dinoseb acetate 12.5 of monolinuron 38.5 of finely divided silicic acid pH 7 8 9.0 k of sodium dinaphthylpH 6.4 6.6

methanedisulfonate 1.1 of sodium alkylbenzene sulfonate 1.4 of partially saponified polyvinyl acetate at the after storage at 50 C for beginning 1 month 2 months 3 months content of DNBP in unstable 1.4 15 discontinued stabilized 1.8 3.8 5.4 6.8 total suspendability in l: unstable 84 63 below 50 stabilized 90 85 79 78 Example 3 Wettable powder with 37.5 percent of dinoseb acetate and 12.5 percent of linuron a) unstable composition b) stabilized 37.5 of dinoseb acetate 12.5 of linuron 37.5 k of finely divided silicic acid pH 7 8 10.0 of sodium dinaphthylpH 6.4 6.6

methane disulfonate 1.1 of sodium alkylbenzene sulfonate 1.4 of partially saponified polyvinyl acetate at the after storage at 50 C for beginning 1 month 2 months 3 months content of DNBP in unstable 0.8 23 stabilized 1.8 3.8 5.0 6.6 total suspendability in unstable 81 56.8 stabilized 85 82 81 80 Example 4 Wettable powder with 37.5 percent of dinoseb acetate and 12.5 percent of diuron a) unstable composition b) stabilized 37.5 of dinoseb acetate 12.5 of diuron 38.5 of finely divided silicic acid pH 7 8 9.0 of sodium dinaphtylpH 6.4 6.8

methane disulfonate 1.1 of sodium alkylbenzene sulfonate 1.4 k of partially saponified polyvinyl acetate at the afier storage at 50 C for beginning 1 month 2 months 3 months content of DNBP in unstable 1 .5 l5 .5 discontinued stabilized 1.5 3.5 5.0 6.6 total suspendability in unstable 86 70 S2 stabilized 88 85 78 77 Example 5 Wettable powder with 37.5 percent of dinoseb acetate and 12.5 percent of monuron is) unstable com sition b) stabilized 37.5 k of dinoseb acetate 12.5 of monuron 38.5 o1 finely divided silicic acid pH 7 8 9.0 of sodium dinaphthylmethane pH 6.4 6.8

disulfonate 1.1 of sodium alkylbenzene sulfonate 1.4 k of partially saponified polyvinyl acetate at the alter storage at 50 C for beginning 1 month 2 months 3 months content of DNBP in k unstable 1.0 17.5 discontinued stabilized 1.1 I: 3.7 k 4.9 k 6.5 total suspendability in unstable 80 60.2 5.1 stabilized 86 83 78 77.5

Example 6 a) unstable composition 37.5 k of dinoseb acetate b) stabilized 12.5 of neburon 37.5 k of finely divided silicic acid pH 7 8 10.0 of sodium dinaphthylmethane pH 6.4 6.8

disult'onate 1.1 of sodium alkylbenzene sulfonate 1.4 of partially saponified polyvinyl acetate at e after storage at 50 C for beginning 1 month 2 months 3 months content of DNBP in k unstable 1.4 15.6 discontinued stabilized 1.3 2.9 5.1 total suspendability in unstable 81 62 50 stabilized 82 80 79 77 Example 7 Binapacryl as wettable powder of 50 percent strength (acaracide) (Phytotoxic damage with a DNBP content of more than 0.6 percent a. unstable formulation 50.0 percent of binapacryl 41.0 percent of finely divided silicic acid 5.0 percent of sodium dinaphthylmethane disulfonate pH 7 8 2.0 percent of sodium alkylnaphthalene sulfonate 2.0 percent of partially saponified polyvinyl acetate at the after storage at 50 C for beginning 1 month 2 months 3 months content of DNBP 0.1 0.4 0.8 1.5 in total suspend- 97 46 27 ability in z b. stabilized formulation 50.0 percent of binapacryl 38.0 percent of Kieselguhr 8.0 percent of sodium dinaphthylmethane disulfonate pH 6.4 6.6 1.0 percent of sodium alkylnaphthalene sulfonate 1.0 percent of sodium alkylbenzene sulfonate 2.0 percent of partially saponified polyvinyl acetate at the afier storage at 50 C for beginning 1 month 2 months 3 months content of ONE? 0.1 0.2 0.4 in total suspend- 93 91 89 88 ability in so Example 8 (acaricide) Wettable powder with 40 percent of binapacryl and 10 percent of tetradifon a) unstable composition b) stabilized 40.0 of bina acryl 10.0 X: of 2,4, ,4-

tetrachlorodiphenyl sulfone (tetradifon) 39.0 I: of kieselguhr pH 7 8 7.0 of sodiumdinapthylmethane pH 6.4 6.8

disulfonate 2.0 of partially saponified polyvinyl acetate 2.0 of sodium alkylnaphthalene sulfonatc at the after storage at 50 C for beginning 1 month 2 months 3 months content of unstable 0.1 0.3 0.9 1.3 stabilized 0.1 0.1 0.1 0.2 total suspendability in unstable 87 70 60 55 stabilized 89 86 82 79.5

Example 9 (acaricide) Wettable powder with 40 percent binapacryl and percent of tetrasul a) unstable com sition b) stabilized 40 of binapacryl 10.0 of 2,4,4',5-tetrachlorodiphenyl sulfide (tetrasul) 9.0 of kieselguhr pH 7 8 7.0 of sodium dinaphthylmethane pH 6.4 6.8 disulfonate 2.0 of partially saponified polyvinyl acetate 2.0 k of sodium alkylnaphthalene sulfonate 30.0 of finely divided silicic acid at the after storage at 50 C for beginning 1 month 2 months 3 months content of DNBP in unstable 0.1 0.3 0.8 1.1 stabilized 0.1 0.1 0.1 0.1 total suspendability in unstable 90 79 64 57 stabilized 88 85 85 79 What is claimed is:

1. In a pesticidal wettable powderformulation comprising a finely-divided solid carrier, at least one dinitro-secbutylphenyl ester as the pesticidal agent, and a dispersing agent, the improvement wherein said formulation comprises, as a stabilizing and dispersing agent, from 4 to percent, by total weight of the formulation, of an incompletely neutralized dinaphthylmethane disulfonic acid sodium salt having free sulfonic acid groups, said salt, if dissolved in water, being capable of forming a 10 percent aqueous solution having a pH value between 5 and 6.8.

2. A formulation as in claim 1 wherein said salt is present in an amount from 6 to 10 percent by total weight of the formulation.

3. A formulation as in claim 1 wherein a 10 percent aqueous solution of said salt has a pH between 6.4 and 6.8.

4. A formulation as in claim 1 wherein said pesticidal agent is acetic acid 2-sec-butyl-4,6-dinitrophenyl ester or 3-methylcrotonic acid 2-sec-butyl-4,6-dinitrophenyl ester.

5. A formulation as in claim 1 wherein said pesticidal agent is 3-methylcrotonic acid 2-sec-butyl-4,6- dinitrophenyl ester in combination with another acaricide selected from the group consisting essentially of 4- chlorophenyl-2,4,5-trichlorophenyl sulfone and 2,4,4',S-tetrachlorodiphenyl sulfide.

6. A formulation as in claim 5 wherein said ester and i dichlorophenyl)- l -methoxyl -methylurea; 3 -(4- chlorophenyl l methoxy-l -methylurea; l-butyl-3- S3 ,4-dichlorophenyl)- l -methylurea; 3-53 4- lchlorophenyl )-l l -dlmethy urea; and -(4- chlorophenyl)-l ,l -dimethylurea.

8.-A formulation as in claim 1 wherein said acetic acid 2-sec-butyl-4,6-dinitrophenyl ester and said urea herbicide are present in a ratio of about 3:1 and in a total amount which is about 50 percent by weight of the formulation. 

2. A formulation as in claim 1 wherein said salt is present in an amount from 6 to 10 percent by total weight of the formulation.
 3. A formulation as in claim 1 wherein a 10 percent aqueous solution of said salt has a pH between 6.4 and 6.8.
 4. A formulation as in claim 1 wherein said pesticidal agent is acetic acid 2-sec-butyl-4,6-dinitrophenyl ester or 3-methylcrotonic acid 2-sec-butyl-4,6-dinitrophenyl ester.
 5. A formulation as in claim 1 wherein said pesticidal agent is 3-methylcrotonic acid 2-sec-butyl-4,6-dinitrophenyl ester in combination with another acaricide selected from the group consisting essentially of 4-chlorophenyl-2,4,5-trichlorophenyl sulfone and 2,4,4'',5-tetrachlorodiphenyl sulfide.
 6. A formulation as in claim 5 wherein said ester and said other acaricide are present in a ratio of about 4:1 and in a total amount which is about 50 percent by weight of the formulation.
 7. A formulation as in claim 1 wherein said pesticidal agent is acetic acid 2-sec-butyl-4,6-dinitrophenyl ester in combination with a urea herbicide which is a member selected from the group consisting of 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea; 3-(4-chlorophenyl)-1-methoxy-1-methylurea; 1-butyl-3-(3,4-dichlorophenyl)-1-methylurea; 3-(3,4-dichlorophenyl)-1,1-dimethylurea; and 3-(4-chlorophenyl)-1,1-dimethylurea.
 8. A formulation as in claim 1 wherein said acetic acid 2-sec-butyl-4,6-dinitrophenyl ester and said urea herbicide are present in a ratio of about 3:1 and in a total amount which is about 50 percent by weight of the formulation. 